client/2.5/FB25Events.pas

(*
 *  Firebird Interface (fbintf). The fbintf components provide a set of
 *  Pascal language bindings for the Firebird API. Although predominantly
 *  a new development they include source code taken from IBX and may be
 *  considered a derived product. This software thus also includes the copyright
 *  notice and license conditions from IBX.
 *
 *  Except for those parts dervied from IBX, contents of this file are subject
 *  to the Initial Developer's Public License Version 1.0 (the "License"); you
 *  may not use this file except in compliance with the License. You may obtain a
 *  copy of the License here:
 *
 *    http://www.firebirdsql.org/index.php?op=doc&id=idpl
 *
 *  Software distributed under the License is distributed on an "AS
 *  IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 *  implied. See the License for the specific language governing rights
 *  and limitations under the License.
 *
 *  The Initial Developer of the Original Code is Tony Whyman.
 *
 *  The Original Code is (C) 2016 Tony Whyman, MWA Software
 *  (http://www.mwasoftware.co.uk).
 *
 *  All Rights Reserved.
 *
 *  Contributor(s): ______________________________________.
 *
*)
{************************************************************************}
{                                                                        }
{       Borland Delphi Visual Component Library                          }
{       InterBase Express core components                                }
{                                                                        }
{       Copyright (c) 1998-2000 Inprise Corporation                      }
{                                                                        }
{    InterBase Express is based in part on the product                   }
{    Free IB Components, written by Gregory H. Deatz for                 }
{    Hoagland, Longo, Moran, Dunst & Doukas Company.                     }
{    Free IB Components is used under license.                           }
{                                                                        }
{    The contents of this file are subject to the InterBase              }
{    Public License Version 1.0 (the "License"); you may not             }
{    use this file except in compliance with the License. You            }
{    may obtain a copy of the License at http://www.Inprise.com/IPL.html }
{    Software distributed under the License is distributed on            }
{    an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either              }
{    express or implied. See the License for the specific language       }
{    governing rights and limitations under the License.                 }
{    The Original Code was created by InterBase Software Corporation     }
{       and its successors.                                              }
{    Portions created by Inprise Corporation are Copyright (C) Inprise   }
{       Corporation. All Rights Reserved.                                }
{    Contributor(s): Jeff Overcash                                       }
{                                                                        }
{    IBX For Lazarus (Firebird Express)                                  }
{    Contributor: Tony Whyman, MWA Software http://www.mwasoftware.co.uk }
{    Portions created by MWA Software are copyright McCallum Whyman      }
{    Associates Ltd 2011 - 2015                                                }
{                                                                        }
{************************************************************************}
unit FB25Events;
{$IFDEF MSWINDOWS} 
{$DEFINE WINDOWS} 
{$ENDIF}

{$IFDEF FPC}
{$mode delphi}
{$interfaces COM}
{$ENDIF}

interface

uses
  {$IFDEF WINDOWS}Windows, {$ENDIF}Classes, SysUtils, IB, FB25ClientAPI, FB25Attachment,
  IBExternals, IBHeader, syncobjs, FBEvents;

type
  TFB25Events = class;

  { TEventhandlerInterface }

  TEventhandlerInterface = class
  private
    FOwner: TFB25Events;
    {$IFDEF WINDOWS}
    {Make direct use of Windows API as TEventObject don't seem to work under
     Windows!}
    FEventHandler: THandle;
    {$ELSE}
    FEventWaiting: TEventObject;
    {$ENDIF}
  public
    constructor Create(aOwner: TFB25Events);
    destructor Destroy; override;
    procedure eventCallbackFunction(length: short; updated: PAnsiChar);
    procedure WaitForEvent;
    procedure CancelWait;
 end;

  { TFB25Events }

  TFB25Events = class(TFBEvents,IEvents)
  private
    FEventID: ISC_LONG;
    FDBHandle: TISC_DB_HANDLE;
    FEventHandlerThread: TObject;
    FAsyncEventCallback: TEventhandlerInterface;
    FFirebird25ClientAPI: TFB25ClientAPI;
  protected
    procedure CancelEvents(Force: boolean = false); override;
    function GetIEvents: IEvents; override;
  public
    constructor Create(DBAttachment: TFB25Attachment; Events: TStrings);
    destructor Destroy; override;

    {IEvents}
    procedure WaitForEvent; override;
    procedure AsyncWaitForEvent(EventHandler: TEventHandler); override;
  end;

implementation

uses  FBMessages;

type

  { TEventHandlerThread }

  TEventHandlerThread = class(TThread)
  private
    FOwner: TFB25Events;
    FEventHandler: TEventhandlerInterface;
  protected
    procedure Execute; override;
  public
    constructor Create(Owner: TFB25Events; EventHandler: TEventhandlerInterface);
    procedure Terminate;
  end;

  { TEventHandlerThread }

 procedure TEventHandlerThread.Execute;
 begin
   while not Terminated do
   begin
     FEventHandler.WaitForEvent;

     if not Terminated  then
       FOwner.EventSignaled;
   end;
 end;

 constructor TEventHandlerThread.Create(Owner: TFB25Events;
   EventHandler: TEventhandlerInterface);
 begin
   inherited Create(false);
   FOwner := Owner;
   FEventHandler := EventHandler;
   FreeOnTerminate := true;
 end;

 procedure TEventHandlerThread.Terminate;
 begin
   inherited Terminate;
   FEventHandler.CancelWait;
 end;

  {This procedure is used for the event call back - note the cdecl }

 procedure IBEventCallback( ptr: pointer; length: short; updated: PAnsiChar); cdecl;
 begin
   if (ptr = nil) or (length = 0) or (updated = nil) then
     Exit;
   { Handle events asynchronously in second thread }
   TEventhandlerInterface(ptr).eventCallbackFunction(length,updated);
 end;

{ TEventhandlerInterface }

constructor TEventhandlerInterface.Create(aOwner: TFB25Events);
var
  PSa : PSecurityAttributes;
{$IFDEF WINDOWS}
  Sd : TSecurityDescriptor;
  Sa : TSecurityAttributes;
begin
  InitializeSecurityDescriptor(@Sd,SECURITY_DESCRIPTOR_REVISION);
  SetSecurityDescriptorDacl(@Sd,true,nil,false);
  Sa.nLength := SizeOf(Sa);
  Sa.lpSecurityDescriptor := @Sd;
  Sa.bInheritHandle := true;
  PSa := @Sa;
{$ELSE}
  GUID : TGUID;
begin
  PSa:= nil;
{$ENDIF}
  inherited Create;
{$IFDEF WINDOWS}
  FEventHandler := CreateEvent(PSa,false,false,nil);
{$ELSE}
  CreateGuid(GUID);
  FEventWaiting := TEventObject.Create(PSa,false,false,GUIDToString(GUID));
{$ENDIF}
  FOWner := aOwner;
end;

destructor TEventhandlerInterface.Destroy;
begin
{$IFDEF WINDOWS}
  CloseHandle(FEventHandler);
{$ELSE}
  if assigned(FEventWaiting) then FEventWaiting.Free;
{$ENDIF}
  inherited Destroy;
end;

procedure TEventhandlerInterface.eventCallbackFunction(length: short;
  updated: PAnsiChar);
begin
  FOwner.FCriticalSection.Enter;
  try
    if FOwner.FResultBuffer <> nil then
      Move(updated[0], FOwner.FResultBuffer[0], length);
  finally
    FOwner.FCriticalSection.Leave
  end;
//  writeln('Set Event');
  {$IFDEF WINDOWS}
  SetEvent(FEventHandler);
  {$ELSE}
  FEventWaiting.SetEvent;
  {$ENDIF}
end;

procedure TEventhandlerInterface.WaitForEvent;
begin
  {$IFDEF WINDOWS}
  WaitForSingleObject(FEventHandler,INFINITE);
  {$ELSE}
  FEventWaiting.WaitFor(INFINITE);
  {$ENDIF}
//  writeln('Event Wait Ends');
end;

procedure TEventhandlerInterface.CancelWait;
begin
  {$IFDEF WINDOWS}
  SetEvent(FEventHandler);
  {$ELSE}
  FEventWaiting.SetEvent;
  {$ENDIF}
end;


  { TFB25Events }

procedure TFB25Events.CancelEvents(Force: boolean);
begin
  FCriticalSection.Enter;
  try
    if not FInWaitState then Exit;
    with FFirebird25ClientAPI do
      if (Call(isc_Cancel_events( StatusVector, @FDBHandle, @FEventID),false) > 0) and not Force then
        IBDatabaseError;

    FInWaitState := false;
    inherited CancelEvents(Force);
  finally
    FCriticalSection.Leave
  end;
end;

function TFB25Events.GetIEvents: IEvents;
begin
  Result := self;
end;

constructor TFB25Events.Create(DBAttachment: TFB25Attachment; Events: TStrings);
begin
  inherited Create(DBAttachment,DBAttachment,Events);
  FDBHandle := DBAttachment.Handle;
  FFirebird25ClientAPI := DBAttachment.Firebird25ClientAPI;
  OnDatabaseError := FFirebird25ClientAPI.IBDataBaseError;
  FAsyncEventCallback := TEventhandlerInterface.Create(self);
  FEventHandlerThread := TEventHandlerThread.Create(self,FAsyncEventCallback);
end;

destructor TFB25Events.Destroy;
begin
  CancelEvents(true);
  if assigned(FEventHandlerThread) then
    TEventHandlerThread(FEventHandlerThread).Terminate;
  if assigned(FAsyncEventCallback) then
    TEventhandlerInterface(FAsyncEventCallback).Free;
  inherited Destroy;
end;

procedure TFB25Events.AsyncWaitForEvent(EventHandler: TEventHandler);
var callback: pointer;
begin
  FCriticalSection.Enter;
  try
    if FInWaitState then
      IBError(ibxeInEventWait,[nil]);

    FEventHandler := EventHandler;
    callback := @IBEventCallback;
    with FFirebird25ClientAPI do
      Call(isc_que_events( StatusVector, @FDBHandle, @FEventID, FEventBufferLen,
                     FEventBuffer, TISC_CALLBACK(callback), PVoid(FAsyncEventCallback)));
    FInWaitState := true;
  finally
    FCriticalSection.Leave
  end;
end;

procedure TFB25Events.WaitForEvent;
begin
  if FInWaitState then
    IBError(ibxeInEventWait,[nil]);

  FInWaitState := true;
  try
    with FFirebird25ClientAPI do
       Call(isc_wait_for_event(StatusVector,@FDBHandle, FEventBufferlen,FEventBuffer,FResultBuffer));
  finally
    FInWaitState := false;
  end;
end;

end.

Revision:	381
Committed:	Sat Jan 15 00:06:22 2022 UTC (2 years, 10 months ago) by tony
Content type:	text/x-pascal
File size:	10048 byte(s)
Log Message:	Release Candidate 1
#	Content
1	(*
2	* Firebird Interface (fbintf). The fbintf components provide a set of
3	* Pascal language bindings for the Firebird API. Although predominantly
4	* a new development they include source code taken from IBX and may be
5	* considered a derived product. This software thus also includes the copyright
6	* notice and license conditions from IBX.
7	*
8	* Except for those parts dervied from IBX, contents of this file are subject
9	* to the Initial Developer's Public License Version 1.0 (the "License"); you
10	* may not use this file except in compliance with the License. You may obtain a
11	* copy of the License here:
12	*
13	* http://www.firebirdsql.org/index.php?op=doc&id=idpl
14	*
15	* Software distributed under the License is distributed on an "AS
16	* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
17	* implied. See the License for the specific language governing rights
18	* and limitations under the License.
19	*
20	* The Initial Developer of the Original Code is Tony Whyman.
21	*
22	* The Original Code is (C) 2016 Tony Whyman, MWA Software
23	* (http://www.mwasoftware.co.uk).
24	*
25	* All Rights Reserved.
26	*
27	* Contributor(s): ______________________________________.
28	*
29	*)
30	{************************************************************************}
31	{ }
32	{ Borland Delphi Visual Component Library }
33	{ InterBase Express core components }
34	{ }
35	{ Copyright (c) 1998-2000 Inprise Corporation }
36	{ }
37	{ InterBase Express is based in part on the product }
38	{ Free IB Components, written by Gregory H. Deatz for }
39	{ Hoagland, Longo, Moran, Dunst & Doukas Company. }
40	{ Free IB Components is used under license. }
41	{ }
42	{ The contents of this file are subject to the InterBase }
43	{ Public License Version 1.0 (the "License"); you may not }
44	{ use this file except in compliance with the License. You }
45	{ may obtain a copy of the License at http://www.Inprise.com/IPL.html }
46	{ Software distributed under the License is distributed on }
47	{ an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either }
48	{ express or implied. See the License for the specific language }
49	{ governing rights and limitations under the License. }
50	{ The Original Code was created by InterBase Software Corporation }
51	{ and its successors. }
52	{ Portions created by Inprise Corporation are Copyright (C) Inprise }
53	{ Corporation. All Rights Reserved. }
54	{ Contributor(s): Jeff Overcash }
55	{ }
56	{ IBX For Lazarus (Firebird Express) }
57	{ Contributor: Tony Whyman, MWA Software http://www.mwasoftware.co.uk }
58	{ Portions created by MWA Software are copyright McCallum Whyman }
59	{ Associates Ltd 2011 - 2015 }
60	{ }
61	{************************************************************************}
62	unit FB25Events;
63	{$IFDEF MSWINDOWS}
64	{$DEFINE WINDOWS}
65	{$ENDIF}
66
67	{$IFDEF FPC}
68	{$mode delphi}
69	{$interfaces COM}
70	{$ENDIF}
71
72	interface
73
74	uses
75	{$IFDEF WINDOWS}Windows, {$ENDIF}Classes, SysUtils, IB, FB25ClientAPI, FB25Attachment,
76	IBExternals, IBHeader, syncobjs, FBEvents;
77
78	type
79	TFB25Events = class;
80
81	{ TEventhandlerInterface }
82
83	TEventhandlerInterface = class
84	private
85	FOwner: TFB25Events;
86	{$IFDEF WINDOWS}
87	{Make direct use of Windows API as TEventObject don't seem to work under
88	Windows!}
89	FEventHandler: THandle;
90	{$ELSE}
91	FEventWaiting: TEventObject;
92	{$ENDIF}
93	public
94	constructor Create(aOwner: TFB25Events);
95	destructor Destroy; override;
96	procedure eventCallbackFunction(length: short; updated: PAnsiChar);
97	procedure WaitForEvent;
98	procedure CancelWait;
99	end;
100
101	{ TFB25Events }
102
103	TFB25Events = class(TFBEvents,IEvents)
104	private
105	FEventID: ISC_LONG;
106	FDBHandle: TISC_DB_HANDLE;
107	FEventHandlerThread: TObject;
108	FAsyncEventCallback: TEventhandlerInterface;
109	FFirebird25ClientAPI: TFB25ClientAPI;
110	protected
111	procedure CancelEvents(Force: boolean = false); override;
112	function GetIEvents: IEvents; override;
113	public
114	constructor Create(DBAttachment: TFB25Attachment; Events: TStrings);
115	destructor Destroy; override;
116
117	{IEvents}
118	procedure WaitForEvent; override;
119	procedure AsyncWaitForEvent(EventHandler: TEventHandler); override;
120	end;
121
122	implementation
123
124	uses FBMessages;
125
126	type
127
128	{ TEventHandlerThread }
129
130	TEventHandlerThread = class(TThread)
131	private
132	FOwner: TFB25Events;
133	FEventHandler: TEventhandlerInterface;
134	protected
135	procedure Execute; override;
136	public
137	constructor Create(Owner: TFB25Events; EventHandler: TEventhandlerInterface);
138	procedure Terminate;
139	end;
140
141	{ TEventHandlerThread }
142
143	procedure TEventHandlerThread.Execute;
144	begin
145	while not Terminated do
146	begin
147	FEventHandler.WaitForEvent;
148
149	if not Terminated then
150	FOwner.EventSignaled;
151	end;
152	end;
153
154	constructor TEventHandlerThread.Create(Owner: TFB25Events;
155	EventHandler: TEventhandlerInterface);
156	begin
157	inherited Create(false);
158	FOwner := Owner;
159	FEventHandler := EventHandler;
160	FreeOnTerminate := true;
161	end;
162
163	procedure TEventHandlerThread.Terminate;
164	begin
165	inherited Terminate;
166	FEventHandler.CancelWait;
167	end;
168
169	{This procedure is used for the event call back - note the cdecl }
170
171	procedure IBEventCallback( ptr: pointer; length: short; updated: PAnsiChar); cdecl;
172	begin
173	if (ptr = nil) or (length = 0) or (updated = nil) then
174	Exit;
175	{ Handle events asynchronously in second thread }
176	TEventhandlerInterface(ptr).eventCallbackFunction(length,updated);
177	end;
178
179	{ TEventhandlerInterface }
180
181	constructor TEventhandlerInterface.Create(aOwner: TFB25Events);
182	var
183	PSa : PSecurityAttributes;
184	{$IFDEF WINDOWS}
185	Sd : TSecurityDescriptor;
186	Sa : TSecurityAttributes;
187	begin
188	InitializeSecurityDescriptor(@Sd,SECURITY_DESCRIPTOR_REVISION);
189	SetSecurityDescriptorDacl(@Sd,true,nil,false);
190	Sa.nLength := SizeOf(Sa);
191	Sa.lpSecurityDescriptor := @Sd;
192	Sa.bInheritHandle := true;
193	PSa := @Sa;
194	{$ELSE}
195	GUID : TGUID;
196	begin
197	PSa:= nil;
198	{$ENDIF}
199	inherited Create;
200	{$IFDEF WINDOWS}
201	FEventHandler := CreateEvent(PSa,false,false,nil);
202	{$ELSE}
203	CreateGuid(GUID);
204	FEventWaiting := TEventObject.Create(PSa,false,false,GUIDToString(GUID));
205	{$ENDIF}
206	FOWner := aOwner;
207	end;
208
209	destructor TEventhandlerInterface.Destroy;
210	begin
211	{$IFDEF WINDOWS}
212	CloseHandle(FEventHandler);
213	{$ELSE}
214	if assigned(FEventWaiting) then FEventWaiting.Free;
215	{$ENDIF}
216	inherited Destroy;
217	end;
218
219	procedure TEventhandlerInterface.eventCallbackFunction(length: short;
220	updated: PAnsiChar);
221	begin
222	FOwner.FCriticalSection.Enter;
223	try
224	if FOwner.FResultBuffer <> nil then
225	Move(updated[0], FOwner.FResultBuffer[0], length);
226	finally
227	FOwner.FCriticalSection.Leave
228	end;
229	// writeln('Set Event');
230	{$IFDEF WINDOWS}
231	SetEvent(FEventHandler);
232	{$ELSE}
233	FEventWaiting.SetEvent;
234	{$ENDIF}
235	end;
236
237	procedure TEventhandlerInterface.WaitForEvent;
238	begin
239	{$IFDEF WINDOWS}
240	WaitForSingleObject(FEventHandler,INFINITE);
241	{$ELSE}
242	FEventWaiting.WaitFor(INFINITE);
243	{$ENDIF}
244	// writeln('Event Wait Ends');
245	end;
246
247	procedure TEventhandlerInterface.CancelWait;
248	begin
249	{$IFDEF WINDOWS}
250	SetEvent(FEventHandler);
251	{$ELSE}
252	FEventWaiting.SetEvent;
253	{$ENDIF}
254	end;
255
256
257	{ TFB25Events }
258
259	procedure TFB25Events.CancelEvents(Force: boolean);
260	begin
261	FCriticalSection.Enter;
262	try
263	if not FInWaitState then Exit;
264	with FFirebird25ClientAPI do
265	if (Call(isc_Cancel_events( StatusVector, @FDBHandle, @FEventID),false) > 0) and not Force then
266	IBDatabaseError;
267
268	FInWaitState := false;
269	inherited CancelEvents(Force);
270	finally
271	FCriticalSection.Leave
272	end;
273	end;
274
275	function TFB25Events.GetIEvents: IEvents;
276	begin
277	Result := self;
278	end;
279
280	constructor TFB25Events.Create(DBAttachment: TFB25Attachment; Events: TStrings);
281	begin
282	inherited Create(DBAttachment,DBAttachment,Events);
283	FDBHandle := DBAttachment.Handle;
284	FFirebird25ClientAPI := DBAttachment.Firebird25ClientAPI;
285	OnDatabaseError := FFirebird25ClientAPI.IBDataBaseError;
286	FAsyncEventCallback := TEventhandlerInterface.Create(self);
287	FEventHandlerThread := TEventHandlerThread.Create(self,FAsyncEventCallback);
288	end;
289
290	destructor TFB25Events.Destroy;
291	begin
292	CancelEvents(true);
293	if assigned(FEventHandlerThread) then
294	TEventHandlerThread(FEventHandlerThread).Terminate;
295	if assigned(FAsyncEventCallback) then
296	TEventhandlerInterface(FAsyncEventCallback).Free;
297	inherited Destroy;
298	end;
299
300	procedure TFB25Events.AsyncWaitForEvent(EventHandler: TEventHandler);
301	var callback: pointer;
302	begin
303	FCriticalSection.Enter;
304	try
305	if FInWaitState then
306	IBError(ibxeInEventWait,[nil]);
307
308	FEventHandler := EventHandler;
309	callback := @IBEventCallback;
310	with FFirebird25ClientAPI do
311	Call(isc_que_events( StatusVector, @FDBHandle, @FEventID, FEventBufferLen,
312	FEventBuffer, TISC_CALLBACK(callback), PVoid(FAsyncEventCallback)));
313	FInWaitState := true;
314	finally
315	FCriticalSection.Leave
316	end;
317	end;
318
319	procedure TFB25Events.WaitForEvent;
320	begin
321	if FInWaitState then
322	IBError(ibxeInEventWait,[nil]);
323
324	FInWaitState := true;
325	try
326	with FFirebird25ClientAPI do
327	Call(isc_wait_for_event(StatusVector,@FDBHandle, FEventBufferlen,FEventBuffer,FResultBuffer));
328	finally
329	FInWaitState := false;
330	end;
331	end;
332
333	end.
334